The invention relates to a flotation-deinking-device comprising a flotation vessel and at least one inlet for introducing the suspension into the flotation vessel, the flotation vessel being arranged as a staged diffusor in which in the area of the stage transition an air inlet opening is arranged, an accept outlet and an outlet for the froth carrying the attached colour particles. Here, a stage transition means a right-angled stage transition.
Such a flotation-deinking-device is known from DE-OS 35 29 638. In this, a two-staged diffusor for introducing the suspension is described in which air is drawn in either at the stage transition located upstream in the direction of flow or at both stage transitions in order to mix the air into the suspension so that small air bubbles are formed as a result of a turbulent flow to which colour particles in the suspension are able to attach themselves.
Flotation cells are already known in which the suspension-air mixture is tangentially introduced in a horizontal direction into a circular-cylindrical flotation vessel. The air bubbles formed in the diffusor to which the coloured particles have attached themselves swim as a froth in this flotation container up to the surface of the suspension in the flotation vessel. Here, the froth then flows over into a central outlet. At the base of the flotation vessel, the suspension separated from the colour particles is withdrawn as accept.
It is an object of the invention to provide a flotation-deinking-device with which colour particles of a particle size in the range of ca. 60 um to several 100 u in diameter can be separated from the suspension while maintaining a good efficiency.